“There is the book, Inspector. I leave it with you, and you cannot doubt that itcontains a full explanation.”—The Adventure of the Lion’s Mane, Sir Arthur Conan Doyle

In the four years since the fifth edition of this book was published, the field has seen continuedinnovations and improvements. In this new edition, I try to capture these changes whilemaintaining a broad and comprehensive coverage of the entire field. To begin this processof revision, the fifth edition of this book was extensively reviewed by a number of professorswho teach the subject and by professionals working in the field. The result is that, in manyplaces, the narrative has been clarified and tightened, and illustrations have been improved.Beyond these refinements to improve pedagogy and user-friendliness, there have beensubstantive changes throughout the book. Roughly the same chapter organization has beenretained, but much of the material has been revised and new material has been added. Themost noteworthy changes are as follows